1. Field of the Invention
The present invention relates to a technique of relaying multicast frames.
2. Description of the Related Art
Wireless LAN adopts the IEEE 802.11 standard. The IEEE 802.11 standard specifies that an access point should use one of predetermined communication rates or BSS Basic Rate Set for forwarding multicast frames. A minimum value of the BSS Basic Rate Set is usually applied as the communication rate for forwarding multicast frames. This is ascribed to the fact that multicast frames are not subject to retransmission control. The access point may fail to forward a large volume of data, such as IPTV multicast stream data, with a sufficiently high quality to a wireless terminal. One technique has been proposed to cause the access point to convert a received multicast frame to a unicast frame and to forward the converted unicast frame to the wireless terminal at a higher communication rate than the preset communication rate for transmission of multicast frames.
This proposed technique may, however, reduce the user's convenience by conversion of multicast frames to unicast frames and transmission of the converted unicast frames. For example, a wireless terminal with installation of an application which is composed on the premise of reception of multicast frames may be incapable of utilizing received unicast frames converted from multicast frames. This problem is not restricted to the access point for a wireless LAN but is also found in any other communication apparatus, for example, PLC (Power Line Communications) modems.